This invention relates to novel quaternary ammonium salts useful in several applications, including phase-transfer catalysis, corrosion inhibition, inhibition of microbial growth, and development of antistatic agents.
Quaternary ammonium salts in which one of the groups attached to nitrogen is a tertiary alkyl group are known in the literature only for relatively small alkyl groups such as t-butyl or t-octyl. The quaternary salt formed from 1,1,3,3-tetramethylbutanamine is described in Journal of Organic Chemistry, vol. 40, pp. 531-2 (1975).
The problem addressed by this invention is to provide quaternary ammonium salts containing large branched alkyl groups, and methods for use of these salts as biocides, corrosion inhibitors and phase transfer catalysts.
This invention is directed to a compound of formula I: 
wherein R1 is C1-C18 alkyl, C1-C18 polyether alkyl, C1-C18 alkenyl, C1-C18 alkynyl, or C7-C12 aralkyl; R2 is C1-C4 alkyl; R3 is methyl or ethyl; R4, R5 and R6 are independently C1-C21 alkyl, substituted C1-C21 alkyl, C1-C21 alkenyl or substituted C1-C21 alkenyl; Xxe2x88x92n is halide, hydroxide, tetrafluoroborate, phosphate or an organic anion having from 1 to 20 carbon atoms; and n is an integer from 1 to 5;
wherein at least one of R4, R5 and R6 is branched;
and wherein R4, R5 and R6 contain collectively at least nine carbon atoms.
An xe2x80x9calkylxe2x80x9d group is a saturated hydrocarbyl group having from one to twenty-one carbon atoms in a linear, branched or cyclic arrangement. A xe2x80x9cpolyether alkylxe2x80x9d group is an alkyl group comprising an oligomer of an alkyl epoxide, e.g., ethylene oxide or propylene oxide, where the oligomer optionally is end-capped with an alkyl or alkenyl group. An xe2x80x9calkenylxe2x80x9d group is an xe2x80x9calkylxe2x80x9d group in which at least one carbon-carbon single bond has been replaced with a double bond. Substituted alkyl and alkenyl groups are substituted with one or more hydroxy; halo; cyano; alkyl; alkoxy; carbalkoxy; carboxy; amino; alkylamino; or nitro groups, with substitution by one or more halo groups being possible on alkyl or alkoxy groups. An xe2x80x9calkynylxe2x80x9d group is an xe2x80x9calkylxe2x80x9d group in which at least one carbon-carbon single bond has been replaced with a triple bond. Preferably, alkyl, alkenyl and alkynyl groups are acyclic and unsubstituted. An xe2x80x9carylxe2x80x9d group is a substituent derived from an aromatic hydrocarbon compound. An aryl group has a total of from six to twenty ring atoms, and has one or more rings which are separate or fused. Substitution on aryl groups of one or more hydroxy; halo; cyano; alkoxy; alkyl; alkenyl; carbalkoxy; carboxy; or nitro groups is permitted, with substitution by one or more halo groups being possible on alkyl, alkenyl or alkoxy groups. An xe2x80x9caralkylxe2x80x9d group is an xe2x80x9calkylxe2x80x9d group substituted by an xe2x80x9carylxe2x80x9d group.
Xxe2x88x92n is halide, hydroxide, tetrafluoroborate, phosphate, or an organic anion having from 1 to 20 carbon atoms. Organic anions are those containing carbon, with the exception of carbonate, bicarbonate, cyanide, cyanate and thiocyanate, preferably those containing carbon and hydrogen, including, for example, phosphonates, alkoxides, carboxylates, hydrocarbyl sulfates and sulfonates, and chelating carboxylic acids. Xxe2x88x92n is the conjugate base of an acid HmX, having m acidic hydrogen atoms, where mxe2x89xa7n. Preferably, m is no greater than 10. Preferably, the pKa for removal of the most acidic hydrogen atom in the acid HmX is no greater than 17; more preferably the pKa for removal of the most acidic hydrogen atom in HmX is no greater than 9. Preferably, Xxe2x88x92n is selected from the group consisting of halide; hydroxide; alkoxide; alkyl, aryl, aralkyl, alkenyl, and alkylamino carboxylates; alkyl and aryl sulfates; alkyl and aryl sulfonates; phosphates; phosphonates; alkyl, aryl, aralkyl, alkenyl, and alkylamino thiocarboxylates; chelating aliphatic carboxylic acids; and tetrafluoroborate. More preferably, Xxe2x88x92n is selected from the group consisting of halide, alkyl sulfate, aliphatic phosphonate and chelating aliphatic carboxylic acids. Particularly preferred aliphatic phosphonates are the anions derived from aminotrimethylenephosphonic acid (ATMP), diethylenetriamine pentamethylenephosphonic acid (DETA), bis-hexamethylenetriamine-pentaphosphonic acid (BHMT) and hydroxyethylidene diphosphonic acid (HEDP). Particularly preferred chelating carboxylic acids include ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid.
For multivalent acids HmX, e.g., the aforementioned phosphonates, the conjugate base Xxe2x88x92n can have n equal to 1, 2, 3, 4 or 5, up to the number of acidic hydrogen atoms m in the acid HmX. When the conjugate base is formed by neutralization of the acid HmX, the number of equivalents of base used to form the conjugate base will determine the value of n. To maintain charge balance, the number of quaternary ammonium ions in the compound will be equal to n. In a preferred embodiment of the invention, n is 1, i.e., Xxe2x88x92n is Xxe2x88x92. Preferably, Xxe2x88x92 is halide or alkyl sulfate, most preferably iodide or bromide.
Preferably, the quaternary salts of formula I are prepared from tertiary-alkyl primary or secondary amines. Preferably, R4, R5 and R6 in formula I all are alkyl groups. Preferably, formula I represents a mixture of compounds among which there are differences in the alkyl groups R4, R5 and R6. Particularly preferred mixtures of tertiary-alkyl primary or secondary amines are Primene(copyright) BC-9 amine, Primene(copyright) 81-R amine, Primene(copyright) JM-T amine, or Primene(copyright) LA-2 amine, all of which are available from Rohm and Haas Company, Philadelphia, Pa. In each of the first three of these, which are tertiary-alkyl primary amines, the R4R5R6Cxe2x80x94 unit is a mixture of C9-C10, C10-C15, C16-C22 hydrocarbons, respectively. Primene(copyright) LA-2 amine is derived from Primene(copyright) 81-R amine by alkylation of the amine with a single n-C 12 alkyl group. In each of the Primene(copyright) amines, at least one of the R4, R5 and R6 groups is branched. Preferably, R1 is a C1-C12 alkyl group.
In one embodiment of the invention, R4, R5 and R6 all are alkyl. Preferably, R2 and R3 are methyl and Xxe2x88x92 is halide, phosphonate or a chelating carboxylic acid. More preferably, R1, R2 and R3 all are methyl and Xxe2x88x92 is bromide or iodide. Preferably, R4, R5 and R6 contain collectively at least ten carbon atoms. More preferably, R4, R5 and R6 contain collectively at least twelve carbon atoms.
The present invention is further directed to a method for inhibiting the growth of microorganisms, including, but not limited to bacteria, fungi, algae and yeasts, by introducing a microbicidally effective amount of the compound to a locus that is subject to microbial attack. The amount of compound to be used depends on the application. Typically the amount of compound of Formula I incorporated into a locus is from 0.1 to 10,000 ppm, preferably from 0.5 to 5,000 ppm and more preferably from 1 to 1000 ppm.
Suitable loci include, for example: cooling towers; air washers; boilers; mineral slurries; wastewater treatment; ornamental fountains; marine structures, such as boats, ships, oil platforms, piers, pilings, docks, elastomeric rubbers and fish nets; marine antifouling coatings, such as marine paints and varnishes; reverse osmosis filtration; ultrafiltration; ballast water; evaporative condensers; heat exchangers; pulp and paper processing fluids; plastics; emulsions and dispersions; paints; latexes; coatings, such as varnishes; construction products, such as mastics, caulks, and sealants; construction adhesives, such as ceramic adhesives, carpet backing adhesives, and laminating adhesives; industrial or consumer adhesives; photographic chemicals; printing fluids; household products, such as bathroom disinfectants or sanitizers; cosmetics and toiletries; shampoos; soaps; detergents; industrial disinfectants or sanitizers, such as cold sterilants, hard surface disinfectants; floor polishes; laundry rinse water; metalworking fluids; conveyor lubricants; hydraulic fluids; leather and leather products; textiles; textile products; wood and wood products, such as plywood, chipboard, flakeboard, laminated beams, oriented strandboard, hardboard, and particleboard; petroleum processing fluids; fuel; crude oil; oilfield fluids, such as injection water, fracture fluids, and drilling muds; agriculture adjuvant preservation; surfactant preservation; medical devices; contact lenses; diagnostic reagent preservation; food preservation, such as plastic or paper food wrap; and pools and spas.
Preferably, the antimicrobial compounds of the present invention are used to inhibit the growth of microorganisms at a locus selected from petroleum processing fluids; fuel; crude oil; oilfield fluids, such as injection water, fracture fluids, and drilling muds; cooling towers, mineral slurries, pulp and paper processing fluids, plastics, emulsions, dispersions, paints, latexes, coatings, construction products, marine structures, household products, cosmetics, toiletries, shampoos, soaps, detergents, industrial cleaners, metalworking fluids, textiles and textile products, wood and wood products, surfactants and diagnostic reagents.
Optionally, the compounds of Formula I can be used in combination with other microbicidal compounds. Formulated compositions comprising an effective amount of a compound of Formula I with an acceptable carrier may be used or the compounds may be applied directly to the end-use environment.
The present invention is further directed to a method for performing reactions with phase transfer catalysis by the compound of formula I, i.e., performing heterogeneous ionic reactions in a two-phase reaction system containing an organic phase and an aqueous phase in the presence of a compound of formula I.
The present invention is further directed to a method for inhibiting corrosion of metals by incorporation of a compound of formula I into a fluid in contact with a metal. Preferably, the metal is steel or copper. Preferably, the concentration of the compound of formula I in the fluid is from 100 ppm to 5%.
The present invention is further directed to a method for extracting metal ions from an aqueous phase into an organic phase by contacting a metal-containing aqueous phase, an organic phase and at least one compound of formula I. Preferred metals include, for example, alkali and alkaline earth metals, gold, cadmium, cobalt, iron, molybdenum, rare earth metals, tungsten, uranium, vanadium and zinc.
The present invention is further directed to a method for decreasing the undesirable effects resulting from the presence of a static charge on a surface by treating the surface with a compound of formula I.
In one embodiment of the invention, the compounds of formula I are prepared by treating the corresponding tertiary-alkyl primary or secondary amine with an excess of an alkylating agent, R3X, for example, an alkyl halide in the presence of a base. Useful bases include sodium and potassium hydroxide, although those skilled in the art will recognize that other bases are suitable. Typically, the reaction is performed in a two-phase mixture of the tertiary-alkyl primary or secondary amine and an aqueous base solution, although it is also possible to perform the reaction in a single-phase solvent or solvent mixture. This method will be referred to as xe2x80x9cRoute A.xe2x80x9d
In another embodiment of the invention, the compounds of formula I are prepared in two steps: alkylating a tertiary-alkyl primary or secondary amine to form a tertiary amine, and then treating the tertiary amine with an excess of an alkylating agent, for example, an alkyl halide. The initial alkylation of the tertiary-alkyl primary or secondary amine is performed by any standard alkylation procedure known to be suitable for this purpose, for example, methylation with formaldehyde and formic acid. The subsequent reaction with an alkylating agent does not require the presence of a base, and typically would be performed in a one-phase organic solvent system. This method will be referred to as xe2x80x9cRoute B.xe2x80x9d
In one embodiment of the invention, the anion Xxe2x88x92 which is derived from the alkylating agent, R3X, is replaced with another anion Xxe2x88x92 by means of an ion exchange process.
Preferably, the alkylating agent, R3X, used to prepare the quaternary salt is a methylating agent or an ethylating agent in which R3 is methyl or ethyl, and X is halo, alkyl sulfate, tosylate, triflate or mesylate. Most preferably, the alkylating agent is methyl iodide or methyl bromide.
When the groups R1, R2 and R3 all are methyl, the product is a tertiary-alkyl trimethylammonium salt. This salt is prepared either by Route A or Route B. Route A for this salt is illustrated by the following scheme: 
This process typically is carried out in the presence of two equivalents of base to neutralize the HX produced by the reaction. Route B for this salt is illustrated by the following scheme: 